Combination lock



FIG. 1 shows a perspective view of the present design;

FIG. 2 shows a front elevational view of the present design;

FIG. 3 shows a rear elevational view of the present design;

FIG. 4 shows a left elevational view of the present design;

FIG. 5 shows a right elevational view of the present design;

FIG. 6 shows a top plan view of the present design;

FIG. 7 shows a bottom plan view of the present design; and,

FIG. 8 shows a front elevational view thereof, with the broken-line disclosure of a locked element being for illustrative purposes only and forming no part of the claimed design. 

The ornamental design for a "combination lock", as shown and described. 